I just find this link which allow to send mail with attachment programmaticaly using only one class
here it is : 
    import java.util.Date;
import java.util.Properties;
import javax.activation.CommandMap;
import javax.activation.DataHandler;
import javax.activation.DataSource;
import javax.activation.FileDataSource;
import javax.activation.MailcapCommandMap;
import javax.mail.BodyPart;
import javax.mail.Multipart;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;
public class Mail extends javax.mail.Authenticator {
    private String _user;
    private String _pass;
    private String[] _to;
    private String _from;
    private String _port;
    private String _sport;
    private String _host;
    private String _subject;
    private String _body;
    private boolean _auth;
    private boolean _debuggable;
    private Multipart _multipart;
    public Mail() {
        _host = "smtp.gmail.com"; // default smtp server
        _port = "465"; // default smtp port
        _sport = "465"; // default socketfactory port
        _user = ""; // username
        _pass = ""; // password
        _from = ""; // email sent from
        _subject = ""; // email subject
        _body = ""; // email body
        _debuggable = false; // debug mode on or off - default off
        _auth = true; // smtp authentication - default on
        _multipart = new MimeMultipart();
        // There is something wrong with MailCap, javamail can not find a
        // handler for the multipart/mixed part, so this bit needs to be added.
        MailcapCommandMap mc = (MailcapCommandMap) CommandMap
                .getDefaultCommandMap();
        mc.addMailcap("text/html;; x-java-content-handler=com.sun.mail.handlers.text_html");
        mc.addMailcap("text/xml;; x-java-content-handler=com.sun.mail.handlers.text_xml");
        mc.addMailcap("text/plain;; x-java-content-handler=com.sun.mail.handlers.text_plain");
        mc.addMailcap("multipart/*;; x-java-content-handler=com.sun.mail.handlers.multipart_mixed");
        mc.addMailcap("message/rfc822;; x-java-content-handler=com.sun.mail.handlers.message_rfc822");
        CommandMap.setDefaultCommandMap(mc);
    }
    public Mail(String user, String pass) {
        this();
        _user = user;
        _pass = pass;
    }
    public boolean send() throws Exception {
        Properties props = _setProperties();
        if (!_user.equals("") && !_pass.equals("") && _to.length > 0
                && !_from.equals("") && !_subject.equals("")
                && !_body.equals("")) {
            Session session = Session.getInstance(props, this);
            MimeMessage msg = new MimeMessage(session);
            msg.setFrom(new InternetAddress(_from));
            InternetAddress[] addressTo = new InternetAddress[_to.length];
            for (int i = 0; i < _to.length; i++) {
                addressTo[i] = new InternetAddress(_to[i]);
            }
            msg.setRecipients(MimeMessage.RecipientType.TO, addressTo);
            msg.setSubject(_subject);
            msg.setSentDate(new Date());
            // setup message body
            BodyPart messageBodyPart = new MimeBodyPart();
            messageBodyPart.setText(_body);
            _multipart.addBodyPart(messageBodyPart);
            // Put parts in message
            msg.setContent(_multipart);
            // send email
            Transport.send(msg);
            return true;
        } else {
            return false;
        }
    }
    public void addAttachment(String filename) throws Exception {
        BodyPart messageBodyPart = new MimeBodyPart();
        DataSource source = new FileDataSource(filename);
        messageBodyPart.setDataHandler(new DataHandler(source));
        messageBodyPart.setFileName(filename);
        _multipart.addBodyPart(messageBodyPart);
    }
    @Override
    public PasswordAuthentication getPasswordAuthentication() {
        return new PasswordAuthentication(_user, _pass);
    }
    private Properties _setProperties() {
        Properties props = new Properties();
        props.put("mail.smtp.host", _host);
        if (_debuggable) {
            props.put("mail.debug", "true");
        }
        if (_auth) {
            props.put("mail.smtp.auth", "true");
        }
        props.put("mail.smtp.port", _port);
        props.put("mail.smtp.socketFactory.port", _sport);
        props.put("mail.smtp.socketFactory.class",
                "javax.net.ssl.SSLSocketFactory");
        props.put("mail.smtp.socketFactory.fallback", "false");
        return props;
    }
    // the getters and setters
    public String getBody() {
        return _body;
    }
    public void setBody(String _body) {
        this._body = _body;
    }
    public String[] get_to() {
        return _to;
    }
    public void setTo(String[] _to) {
        this._to = _to;
    }
    public String get_from() {
        return _from;
    }
    public void setFrom(String _from) {
        this._from = _from;
    }
    public String get_subject() {
        return _subject;
    }
    public void setSubject(String _subject) {
        this._subject = _subject;
    }
    // more of the getters and setters …..
}
and here is an example of using it : 
new AsyncTask<String, String, String>() {
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            Utils.getProgressDialog(CheckedListActivity.this);
        }
        boolean success = false;
        @Override
        protected String doInBackground(String... params) {
            Mail m = new Mail("username@gmail.com", "password"); 
              String[] toArr = {"sdfdfvg@gmail.com", "sdcfsdfdsf@hotmail.com"}; 
              m.setTo(toArr); 
              m.setFrom("username@gmail.com"); 
              m.setSubject("MyApp COMMANDE TEST"); 
              m.setBody("MyApp COMMANDE TEST contenu"); 
              try { 
                m.addAttachment("/sdcard/MyAPP/liste_clients.xls"); 
                if(m.send()) { 
                    success = true;                 
                } else { 
                    success = false;                      
                } 
              } catch(Exception e) {                   
                Log.e("MailApp", "Could not send email", e); 
              } 
            return null;
        }
        @Override
        protected void onPostExecute(String result) {
            Utils.dismissProgressDialog();
            if(success){
                Utils.showAlertDialog(CheckedListActivity.this, "Envoi reussi", "Votre message est envoyé avec succée");
            }else{
                Utils.showAlertDialog(CheckedListActivity.this, "Echec d'envoi", "Votre message n'est pas envoyé, veuillez ressayer");
            }
        }
    }.execute();
and the mail is received in real time which is not the case for the other class
here is the src link :  here
and of course we have to add those jar : 
mail
activation
additionnal
I hope it helps